Orbital simulation facility

ABSTRACT

A method and apparatus for determining the orientation of a spacecraft in orbit around a central body and providing a simulated representation of the surface of the central body as seen from the spacecraft. A spherical model representing the central body is rotated by a motor-driven frictional belt drive. The axis of rotation is established by an adjustable vacuum cup device and an optical system projects a virtual image of the central body&#39;&#39;s surface as telemetered from a spacecraft onto the model. A viewing aperture is moved in relation to the model until the virtual image and a reflected image from the model coincide to produce the same view as from the spacecraft.

United States atent [191 Harpe et al.

[54] ORBITAL SIMULATION FACILITY [75] Inventors: Ralph W. Harpe, Houston, Tex.;

Henry S. Schrader, Vienna, Va.

Assignee: The United States of America as represented by the Secretary of the Army [22] Filed: Mar. 19, 1971 [21] Appl. No.: 126,221

[111 3,734,6i3 1 May 22,1973

Primary Examiner-John M. Horan Attorney-Charles K. Wright, Jr., William G. Gapcynski and Lawrence A. Neureither [57] ABSTRACT A method and apparatus for determining the orientation of a spacecraft in orbit around a central body and providing a simulated representation of the surface of the central body as seen from the spacecraft. A spherical model representing the central body is rotated by a motor-driven frictional belt drive. The axis of rotation is established by an adjustable vacuum cup device and an optical system projects a virtual image of the central bodys surface as telemetered from a spacecraft onto the model. A viewing aperture is moved in relation to the model until the virtual image and a reflected image from the model coincide to produce the same view as from the spacecraft.

13 Claims, 16 Drawing Figures 3 PATENTE ILL-X22 I975 SHEEI10F6 RALPH w. HARPE a. HENRY s. SCHRADER ATTORNEY PATENTED W22 I973 FIG.3

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ATTORNEY PATENIE ma 2 2 I913 SHEET 6 [1F 6 I ll INVENTORS RALPH W. HARPE 8n ATTORNEY ORBITAL SIMULATION FACILITY The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to us of any royalty thereon.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention is used to determine the complete orientation of a spacecraft in selenocentric coordinates for all six degrees of freedom of the spacecraft over an unknown part of the surface of a central body such as the moon. It is also used, once these six degrees of freedom are determined relative to a pass of the spacecraft over a specific unknown part of the celestial body's surface, to reconstruct a photographic image of that part and eventually all of the surface.

2. Description of the Prior Art U.S. Pat. No. 3,070,792 discloses the use of a translucent shell mapped out to represent a terrestrial hemisphere. By the use of a lens, a map image is taken from the shell and displayed on a translucent plotting surface. A vertical radar screen showing the terrain below an aircraft is placed near the plotting board with a half silvered mirror imposed so that the map image on the plotting surface can be compared with the presentation on the radar screen. The shell is supported and positioned by belt driven wheels operated by motors controlled in their speed by a track angle signal coming from a navigational computer.

U.S. Pat. No. 3,058,239 discloses a globe structure supported for rotation about two axes normal to each other, having a shaft disposed diametrically within the globe and projecting from the surface ofthe globeat one point to a semicircular yoke member which extends along a portion of the circumference of the globe. Movements of the globe necessary for tracking may be effected automatically by electrical pulses or by manual operation.

U.S. Pat. No. 3,405,462 discloses another sphere supported on driving wheels that frictionally drive the sphere. Control of the direction of rotation may be achieved either by the use of a caged weight which tends to maintain the rotation along a particular circumference or by a controllable steering wheel upon which the sphere rests.

U.S. Pat. No. 3,377,719 discloses a rotatable globe with two motor driven friction wheels which engage the globe at two selected great circles in planes at right angles to each other thus enabling the globe to be rotated along any desired component path.

U.S. Pat. No. 3,137,531 discloses a gaseous bearing for use in supporting a space vehicle motion simulator with a support ring attached to the upper periphery of a support housing. A cup which is slidably engaged with the inside of the housing raises the sphere off the ring when air pressure is applied. When the air pressure is turned off a spring draws the cup downward allowing the ball to again rest on the ring. An air actuated brake pad is slidably engaged in the center of the cup for stopping the motion of the ball.

SUMMARY OF THE INVENTION The orbital simulation facility is used primarily to determine the exact orientation of a spacecraft in selenocentric coordinates for all six degrees of freedom of the spacecraft over an unknown part of a central body such as the moon. The spacecraft should be provided with conventional optical aspect systems and sensors. Data is telemetered from the spacecraft and visually matched with a known part of the lunar surface as simulated on a spherical model hereafter referred to as the lunar model which is secured by elevational and rotational assemblies. An operator can rotate and elevate the lunar model to simulate the passage of the spacecraft over identical points on the lunar model as on the moon. Video images are projected onto the model by a projection printer.

The lunar model is supported by a ball and air column system constructed in a spherical disk shaped rotating support. An air column with a multiplicity of air outlets enables pressurized air to be exerted against suspended balls restrained in outlet chambers by retainer rings.

The lunar model and its basic support are positioned on a main horizontal beam which is secured to vertical support posts preferably a Saginaw ball screw jack variety. The elevation of the beam and lunar model are controlled by a motor, which, through a pinion and gear system, drives the beam up or down the jacks.

The lunar models rotational assembly utilizes a curved beam which partially encircles the model and is secured to a rotational sleeve around a vertical projection from the dish-like model support. Two assemblies operate from and are driven by motors around tracks on the curved beam. One assembly is a mechanism for establishing a rotational axis about which the lunar model can be spun. The axis is set by a beam of light through a hollow axle of the axis mechanism which coincides with a precisely known reference point on the model. The axis mechanism, like the models support, is an air activated device which has a vacuum-acting ring to secure the lunar model over the point where the light beam strikes thus establishing a rotational axis.

The second mechanism projecting from the curved beam is a rotation or spin mechanism. Its propose is to rotate the lunar model about the axis set by the axis fixing mechanism described above. The rotational mechanism is a belt and pully device which frictionally engages the surface of the lunar model to rotate it about its spin axis. The rotational mechanism projects from a track on the opposite side of the curved beams from the axis mechanism so that both mechanisms have the freedom to be driven the entire length of the curved beam. Thus, the lunar model can be grasped by the annular vacuum gripping mechanism and rotated about its axis by the simulator operator.

The prior systems do not disclose means for achieving the three degrees of freedom of rotation for the simulator model necessary to accurately simulate a central body. The use of restricting supports which penetrate the spherical model, belt drives, or wheels restrain the model and limit its effectiveness. Gaseous bearings heretofore used have not provided a support with the necessary degree of stability to effectively and precisely simulate orbital operations.

Accordingly, it is an object of this invention to provide an orbital simulation facility capable of utilizing data telemetered from a spacecraft engaged in orbital maneuvers and which simulates a like situation on the simulator model as on the surface of the central body about which the spacecraft is orbiting.

It is a further object of the invention to provide an orbital simulator facility whereby spacecraft video signal data may be projection printed on a lunar model for purposes of duplicating a complete mosaic of all parts of the lunar surface.

It is a still further object of the invention to provide an orbital simulator facility having a sphere support which will allow three degrees of freedom of rotation of the sphere.

It is another object of the invention to provide an orbital simulator facility that has the means to precisely select the axis of rotation of the simulator model at any point in a hemispheric area and then provide a method of rotating the model about the selected axis after axial determination has been made.

It is still another object of the invention to provide a mechanical system to move the simulator model up or down using the viewing center line as a zero reference.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the orbital simulation facility;

FIG. 2 is an elevational view of the simulators lunar model support and rotational assemblies;

FIG. 3 is a vertical cross-sectional view of te air bearing support for the lunar model;

FIG. 4 is a vertical cross-sectional view of the simulators lunar model axis fixing mechanism;

FIG. 5 shows the carrier for the axis fixing mechanism;

FIG. 6 is an elevational view of the vacuum support of the axis fixing mechanism;

FIG. 7 is a plan view of FIG. 6;

FIG. 8 is a side view of the simulators lunar model rotation imparting mechanism;

FIG. 9 shows the carrier for the rotation mechanism;

FIG. 10 is a schematic layout of the simulators lunar model elevation mechanism;

FIG. 11 shows the pinion and gear system for the upper drive shafts of the elevation mechanism;

FIG. 12 shows the motor and coupling for the elevation mechanism;

FIG. 13 shows the bearing cell for elevation mechanism;

FIG. 14 shows the screw ball nut connection for the elevation mechanism;

FIG. 15 shows the frame base plate; and

FIG. 16 shows the motor and gear for the rotational curved beam.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, the simulator and its system comprise the following principal components; a dark tunnel type of container or housing 10 which may be constructed of any suitable materials and in any suitable shape, a lunar model 24 which has a photosensitive surface, the elevational and rotational assembly for the lunar model generally indicated by components 7, 8, l2, l8 and 80, the viewing aperture 21 and control 22, and the projection printing means 23.

The simulator operator standing or seated in front of the viewing aperture 21 and using the control 22 excites the lunar model 24 which be visually matches with respect to the determination of the location of its spin axis through known features on the moon model and features in the scan line of the image contained in the projection printer 23 causing the image to be projected on the lunar model 24. When a visual match occurs the lunar orbit is simulated and can be determined.

The simulator operator can then use control 22 manually and rotate and elevate the moon model 24 to simulate the passage of the spacecraft over identical points on the surface of the moon. With the simulator enclosed by surfaces 10 to constitute a dark tunnel, the video images projected by projection printer 23 can be printed upon the photosensitive surface of lunar model 24. The projection printer 23 includes a conventional slit printing device which operates in response to the control 22 to project relatively sequenced video images or mosaics on the sensitized model 24.

Referring to FIG. 2, the sphere 24 is supported by the spherical disk shaped rotating support 9 which rests on base tube 17 which is mounted on main beam 12. The base tube 17 is also used as a bearing tube for the curved beam assembly sleeve 14. Curved beam 18 is rigidly secured to the sleeve 14 and the simulators rotational axis mechanism 7 and sphere rotation mechanism 8 project from the curved beam 18 to the sphere 24. Support 9 houses a ball and air column support system for the lunar model 24 illustrated in detail in FIG. 3.

The surface of the model 24 is coated with a photographic emulsion and must not be damaged during the manipulation operation. The top of the sphere support housing 9has 50 orifices 6 which connect with an air chamber 30 in the bottom of the housing 9 (FIG. 3). Fifty teflon balls 33 are arranged in three circles stepped to match the spherical contour of the model 24. Air pressure lines 32 connected to the air chamber exert pressure on the teflon balls 33 supporting the sphere. The balls 33 are retained in their orifices 6 by teflon rings 34 which prevent their escape. Regulators (not shown) in the air lines adjust the pressure, as necessary, to carry the sphere load. The support housing 9 is bolted to the base tube 17 which in turn is attached to the main beam 12.

Curved beam 18 (FIG. 1) slidably engages mechanisms 7 and 8 and the simulator operator using control 22 can remotely actuate the lunar model 24 which is rotated by the rotation mechanism 8 around the spin axis set by the vacuum axis mechanism 7. Support beam 18 contains a gear sector 51 which axis mechanism 7 can climb as the relative spin axis changes position.

The curved beam 18 encompasses the sphere model through an arc of and the beam 18 is permitted a horizontal rotation through 180 allowing an axis of rotation to be selected anywhere within a hemispheric area on the lunar model 24.

The simulators lunar model spin or rotational axis mechanism 7 is shown in FIGS. 4-7. The axis mechanism 7 is motor driven over the length of the curved beam 18 to provide positioning over the desired rotation axis. A ring type vacuum cup 35, centered over the axis, is dropped onto the model surface and fastened by vacuum. A small light spot, centered in the vacuum cup 35, focused on the model surface, indicates the exact center of the axis of rotation. The openings created by the vacuum cup mount ribs 36 allow an observer to view the light spot and model surface during the selection of the rotation axis. Once the axis of rotation is established, the vacuum cup carrier 37 remains stationary on the curved beam 18. The sphere rotation mechanism 8 then rotates the model 24 about the axis.

The vacuum cup 35 is cemented to a metal ring mount 38. The three ribs 36 attach the metal ring 38 to a tube 39. The ring 38 and ribs 36 are drilled to match the vacuum cup apertures and provide the vacuum function. The vacuum cup tube 39 slides and rotates in a nylon bearing plate 40 which is bolted to the bottom of the support box 41. A ring plate 42 attached to the top of the vacuum cup tube 39 keeps it from slipping out of the support box 41. The support box 41 contains a tapped hole for attaching the vacuum line 43. The vacuum path can be described as going through the support box 41, vacuum cup tube 39, three hollow ribs 36, metal mounting ring 38 to the vacuum cup. A shaft 44 in the support box 41, contains two pins (not shown) which act as levers on the vacuum tube plate 42 to lift from or drop the vacuum cup 35 on the lunar model 24. A lifting handle 45 on the end of the shaft outside the support box 41 is used to hold the vacuum cup assembly in a disengaged position through a spring 46 and detent pin 47 in the handle 45 which detents on the support box 41. The support box 41 is mounted on the carrier 37 which has four wheels 48 for travel up and down the curved beam. A DC motor 49 is mounted on the carrier 37 to engage the gear racks 51 on the curved beam 18 and thus provide the means of moving the carrier 37 up and down the beam 18.

Part of the optical system producing the light spot is mounted in the vacuum cup mount 38 to make the spot center coincident with the axis of rotation of the vacuum cup 35. A single lens 50, cemented in the center of the vacuum cup mount ring 38, images a lighted aperture assembly into a light spot. The lighted aperture comprises an aperture plate 52, an aperture 53 and a ground glass disk 54 mounted in the side of the support box 41. A lamp 55 is a sheet metal housing 56 is fixed on the outside of the support box 41 to illuminate the aperture 53. A small mirror 57 inside the support box 41 supported directly over the vacuum cup tube 39 reflects the lighted aperture 52 toward the lens 50.

Referring now to FIGS. 8 and 9 since the axis mechanism 7 travels on one side of the curved beam 18, the sphere rotation mechanism 8 travels on the other side to allow the mechanisms 7, 8 to pass each other and es- I tablish an axis of rotation at either end of the curved beam 18. The function of the sphere rotation mechanism 8 is to revolve the lunar model 24 about the selected axis of rotation. This is accomplished by applying a pulley mounted, motor driven, rubber belt 58 to the model surface ninety degrees from the axis of rotation.

The rotation mechanism carrier 59 has four wheels 60 which ride in the tracks 61 of the curved beam 18. A DC. motor 77 is mounted on the carrier 59 to engage the gear sector 51 on the curved beam 18 and thus provide the means of moving the mechanism 8 along the beam 18. A belt drive plate 62 is bolted to the carrier 59 so that the mechanism 8 is always perpendicular to the lunar model surface. The plate carries the belt 58 and a drive motor 73. The continuous belt 58 is preferably a rubber fabric type. A belt drive arm 66 has two pulleys 67, and a round rod 68 extending from its center. The portion of the belt 58 between pulleys 67 contacts the sphere 24 for rotation. The round rod 68 slides in a nylon bearing block 69, bolted to the belt drive plate 62 allowing the arm 66 to be moved toward or away from the sphere surface. Minimum clearance between the arm 66 and the plate 62 prevents the arm 66 from rotating out of position. A pressure spring 70, around the rod 68, between the arm 66 and the bearing block 69 provides the necessary pressure to keep the belt 58in contact with the sphere 24. From the two pulleys 67 on the arm 66, the belt 58 passes over a fixed pulley 71 on the plate 62 to the drive motor pulley 72. A drive motor 73 is fastened to-the belt drive plate 62. A solenoid 74 is clamped to the plate 62 in line with the nylon bearing block 69 and functions to pull the arm 66 and belt 58 away from the sphere surface when the mechanism 8 needs to be moved to another driving position. The slack in the belt 58 is taken up by a spring loaded idler arm 75 and pulley 76, mounted on the plate 62 between the driving arm 66 and the drive motor pulley 72. The belt drive 72 and carrier motors 77 are controlled from the remote control panel 22.

FIGS. 10-16 illustrate details of the simulators lunar model elevating mechanism 80 used to move the lunar model 24 up or down with respect to the viewing axis. While viewing the virtual image the observer through a switch on control panel 22 moves the model 24 vertically until he matches the virtual image with the photographic information on the lunar model 24.

Lunar model 24 rests on support 9 containing the air pressure activated balls 33 as shown in FIG. 3. Support 17 holds support 9 and rests on the moveable main beam 12 which in turn moves up and down Saginaw ball screw jacks 11 used as support posts as these are rotated by a DC. motor 81 and pinion and gear system 82.

A screw 83 and ball nut 84, have helical races (not shown) in which ball bearings (not shown) circulatef Two flanged ballnuts 84 on each screw 83 are used to F support the main beam 12 which carries the lunar model 24. Two of these screws 83 are mounted in ball bearings 86, 87, top and bottom. The bottom bearings 87 are mounted in base plates 88 attached to the floor. The upper bearings 86 are mounted in cells 89 attached to wall brackets 90 bolted to the walls. The cells 89 in wall brackets 90 contain a separate set of ball bearings 91 which support the lower ends of upper shafts 92. The lower ends of these shafts 92 are slotted to engage the tongue (not shown) on the Saginaw screws 83. The tops of the upper shafts 92 which are fastened to bevel gear pinions 93 are mounted in ball bearings 94 attached to the wall brackets 90. A drive shaft 95 having two bevel gears 96 to engage the pinions 93 on the upper shafts 92 is mounted in ball bearings 97 supported on the top of each wall bracket 90. One of the ball bearing mounts 97 for this shaft 95 is used to support the drive motor 81 and shaft-motor coupling 16. The DC. motor 81 is used to drive the Saginaw screws 11 and in turn raise or lower the main beam 12 and lunar model 24. The main beam 12 is supported be tween the two Saginaw screws 11 by bolting it and uprights 13 to the ballnuts 84. The drive motor 81 is controlled from the remote control panel 22.

Details of the control 22 are not shown since many types of conventional automatic simulator actuating devices can be readily adapted for use in the simulator to duplicate all six degrees of freedom of the spacecraft. Likewise, many existing conventional means might be readily attached to the projection printing devices of the simulator for purposes of sequentially and automatically receiving, recording and feeding the necessary film positives to the projection printing apparatus. Slit printing shutter type mechanisms likewise are not shown since any such conventional mechanism might be readily used for screening out sequential areas of the photosensitive emulsion coated lunar model 24 that is not positioned to receive a projected selenocentrically coordinated video image. Using Manual" override, the lunar model 24 is positioned and repositioned in elevation, spin axis, rotation, etc., until the projected image matches an image previously referenced or projection printed on the surface of lunar model 24. When this match occurs the lunar model 24 is in the same position with respect to the viewing aperture 21 as the spacecraft was with respect to the moon when the photographic image was first recorded and telemetered to the projection printing receiving, recording, developing and image referencing apparatus 23. Thus, the position of the spacecraft in inertial space is Manually recreated or simulated.

All systems of the simulator can be selectively and Manually activated through the control 22 by varying the current as the driving elements consist of D.C. motors.

When the simulator is manually operated, the projection printing apparatus 23 projects the small photographic image received from the spacecraft upon the ground glass screen 99. This image is then picked up by the half silvered mirror 100 located immediately in front of the operators viewing aperture 21 at an angle of 45, which in turn creates a virtual image on the surface of the lunar model 24. The lunar model 24 then can be remotely elevated, spun and moved in various directions by the operator with the control 22 set at Manual to override automatic programming. The model 24 can be illuminated by the projection printing apparatus 23, and a polarizing filter (not shown) is interposed between the model 24 and the projection printing apparatus 23 to prevent bright spots from appearing on the model 24 and so that the light striking its surface and the projected image will be homogenous or of a predetermined albedo.

The viewing aperture 21 where the simulator operator sits, collects the image on the ground glass screen 99 and presents it as a spatial image tangent to lunar model 24. The viewing aperture consists of an optical beam splitter (not shown) and an iris diaphragm (also not shown). The simulator operator through control 22 Manually remotely manipulates the lunar model 24 and matches the spacecraft collected images with known lunar features already referenced or projection printed on lunar model 24.

Any conventional means may be used to maintain the photosensitive emulsion in constant proper density over the lunar model 24. Likewise, means for developing exposed lunar model surface portions are not shown. The photosensitive emulsion coating used on the lunar model 24 is not materially disturbed by the vacuum support, the frictional rotatable motion imparting mechanism or by the air ball support mechanism.

The simulator utilizes data telemetered from a spacecraft engaged in lunar orbital maneuvers and the data is visually matched with a known part of the lunar surface as selenocentrically simulated on a lunar model. It also establishes means for the projection printing of spacecraft video signal data on a lunar model for purposes of duplicating in perfect registration on the model a complete photographic mosaic of all parts of the lunar surface including the back side" thereof.

A spacecraft whose lunar orbit is to be simulated and measured must be provided with conventional optical aspect systems and sensors.

Depending on the parameters of the lunar orbit the aspect system should be able to provide some or all of the following information after injection into lunar orbit:

a. Spin axis sun angle b. Position of spin axis in inertial space c. Altitude of spacecraft above lunar surface at certain times d. Coordinates of point on lunar surface directly beneath spacecraft at certain times.

The spacecraft lunar orbit could, of course, be partially defined through the use of altitude and coordinate data.

The present invention determines the position of the spin axis as well as the coordinates of the point on the lunar surface directly beneath the spacecraft through simulation of the spacecraft moon relationship. To accomplish this a viewing aperture is placed at a distance from the lunar model 24. By means of the half silvered mirror, a virtual image of the image as actually transmitted from the spacecraft will be projected upon the lunar model. Means are provided to allow a visual match to occur between the model and the transmitted image as seen from the viewing aperture. When this match occurs, the model 24 is manually or automatically positioned with respect to the viewing aperture as the moon was with respect to the spacecraft when the image was transmitted.

This visual match is obtained in the simulator through the use of projector type lantern slides made from the video data transmitted from the spacecraft. Scan lines from a video scanner mounted in the spacecraft will be reproduced or imprinted on a slide. These scan lines will indicate the horizon crossings as seen by the scanner and will have the scanned area properly positioned between the horizon crossings. The scan lines when reproduced or imprinted on a slide, are then projected by the simulators projection apparatus on its screen so that these scan lines are horizontal. During such projection, the simulators half silvered mirror will reflect the image of the scan lines appearing on such a slide into the viewing aperture.

The scan line which is level with the viewing aperture is the line swept out at that instant of time for which the simulator is designed to reconstruct. The procedure for obtaining visual match is as follows:

Adjust the size of the image on the simulator screen so that it subtends the proper angle at the viewing aperture.

Position the center of the moon model a distance X m from the viewing aperture so X =(r +h) (r ,,(r) sin 8 (Where r is radius of model and r is radius of moon h is altitude of spacecraft above moon surface, 8 is inclination of spin axis to moon) Raise center of the moon model a distance y above level of viewing aperture where With the scan lines in the horizontal plane on the model of the moon, the spin axis of the spacecraft would be assumed to be vertical and sunlight to be arriving at an angle B from the vertical. This would position the sun as lying in a vertical plane which is positioned at an angle a determined by a line drawn from the viewing aperture through the moon center measured in the opposite direction from the spacecraft rotation.

From this referencing or starting fixation point the simulator operator can now align a highly focused pin point of light (beam) on the moon model [3 from the vertical and 11 in azimuth. At the point where the so focused light (beam) strikes the lunar model 24, the sun would be directly overhead.

The coordinates of the actual point on the lunar surface where the sun is directly overhead can be easily computed. The simulator operator having computed the actual point on the lunar surface where the sun is directly overhead pinpoints the coordinate referencing light (beam) of the simulator on the identical so referenced point on the lunar model 24.

The simulator lunar model 24 now has but one degree of freedom which has not been uniquely determined. This would be the moon models rotation about the axis fixed by the aforesaid pinpointing light (beam).

As stated previously, the simulator is provided with an annular vacuum gripping mechanism 7 centered about the pinpointing light (beam) and capable of engaging the moon model in a manner that will permit its rotation about such light beam axis of rotation. The simulator operator can now engage the moon model surface with the annular vacuum gripping device and rotate the model about such an axis.

When a visual match occurs between the features on the model and the features on the scan line being 'compared, the position of the spacecraft with respect to the lunar surface has been simulated for purposes of comparative analysis. The point directly on top of the lunar model 24 now indicates the direction of the spacecraft spin axis. The point on the lunar model 24 intercepted by the line drawn from the viewing aperture to the center of the lunar model 24 is the point on the moon directly under the spacecraft.

It is thus possible to obtain the complete orientation of a spacecraft with respect to a central body such as the moon, defined in selenocentric coordinates for all 6 degrees of freedom of the spacecraft.

Likewise, once the 6 degrees of freedom are known for a pass of the spacecraft over an unknown part of the lunar surface, a photographic image of that part of the lunar surface can be reconstructed.

The simulator is provided with means for orienting the orbit of the spacecraft with reference to the center mass of the moon, namely, it establishes the tracking path of the space vehicle around the lunar surface.

The simulator also provides means whereby the operator can control the rotation of the lunar model 24 about its axis and its relative simultaneously coinciding or other desired movement in the y and z planes. It contains means to control lighting in the various modes.

The simulator could be provided with conventional automatic controls for snychronizing the telemetered data received from a spacecraft into the projection printing apparatus of the simulator. For example, a conventional computer type of attachment could be programmed to activate conventional automatic controls for purposes of duplicating the relative motions of spacecraft to lunar surface and simulator operator to lunar model 24. Likewise, automatic controls to link in \relative spacecraft orbit to lunar surface and video signal to relative projection printed and oriented mosaics using conventional slit" printing technique could be used.

For clarity sake reference throughout the specification has been made to the moon and the lunar model. This language is not to be considered as limiting the utility of the invention which may be used during exploration of any central body including any of the planets.

We claim:

1. An orbital simulation facility comprising:

a. a sphere;

b. air bearing means for supporting said sphere;

c. independent support means partially surrounding said sphere;

d. vacuum means supported by and freely rotatable with respect to said independent support means and adjustably engageable on a portion of the surface of said sphere for establishing an axis of rotation for said sphere; and

e. a first driving means engageable on said sphere for revolving said sphere about said spheres axis as established by said vacuum means.

2. The orbital simulation facility described in claim 1 including a vertical drive means to adjust the elevation of said sphere.

3. The orbital simulation facility described in claim 2 including a remote control means for operating said vacuum means, said first driving means, and said vertical drive means.

4. The orbital simulation facility described in claim 1 wherein said sphere has a photosensitive surface and the facility includes means for projecting images on said photosensitive surface of said sphere.

5. The orbital simulator facility described in claim 1 wherein said air bearing means for supporting said sphere comprises:

a. A sphere support housing having an upper concave side to receive said sphere, said upper concave side having cavities, with said cavities having channels extending within said housing, said channels being of smaller diameter than said cavities;

b. balls of larger diameter than said channels received in said cavities;

c. retaining means around said cavities to prevent said balls from escaping said cavities; and

d. means for connecting a pressurized air supply to, said channels for exerting pressure on said balls causing them to rise as far as permitted by said retaining rings whereby said sphere is supported by the portion of the surface of said balls that rise above said retaining ring when said air supply is turned on.

6. An orbital simulation facility comprising:

a. a sphere;

b. air bearing means for supporting said sphere including a circular pedestal extending downward from said air bearing means;

c. a sleeve rotatable around said circular pedestal;

d. a partial curved beam rigidly attached to said sleeve and extending upward from said sleeve over said sphere;

e. vacuum means extending from and freely rotatable with respect to said curved beam and adjustably engageable on a portion of the surface of said sphere for establishing an axis of rotation for said sphere; and

f. a driving means extending from said curved beam and engageable on said sphere for revolving said sphere about said spheres axis.

7. The orbital simulator facility described in claim 6 wherein said air bearing means for supporting said sphere comprises:

a. a sphere support housing having an upper concave side to receive said sphere, said upper concave side having cavities in concentric arrangement with said cavities having channels of smaller diameter than said cavities extending downward within said housb. balls of larger diameter than said channels received in said cavities;

c. retaining rings around said cavities to prevent said balls from escaping said cavities; and

d. means for connecting a pressurized air supply to said cavities through said channels so that pressure is exerted on said balls causing them to rise as far as permitted by said retaining rings whereby said sphere is supported by the partial surfaces of said balls that rise above said retaining ring when said air supply is operative.

8. The orbital simulation facility described in claim 6 wherein said vacuum means comprises:

a. a vacuum ring engageable on the surface of said sphere; and

b. vacuum control means connected to said vacuum ring for selectively engaging and disengaging said vacuum ring from the surface of said sphere.

9. The orbital simulation facility described in claim 6 wherein said driving means is belt driven and further comprises:

a. a frame slideably attached to said curved beam;

b. an arm adjustably connected to said frame so that the distance between said arm and said frame may be adjusted;

c. pulleys on both said arm and said frame;

d. a belt extending over all of said pulleys;

e. a motor to drive said belt; and

f. means to engage and disengage said belt from the surface of said sphere.

10. The orbital simulation facility described in claim 6 wherein said partial curved beam is in a concentric arrangement with said sphere and includes track means in which said vacuum means and said belt driving means are engaged.

11. The orbital simulation facility described in claim 6 including vertical drive means comprising:

a. a horizontal member for supporting said circular pedestal; b. vertical members attached to the extremities of said horizontal member; and c. jacking means connected to said vertical members for raising and lowering said horizontal member whereby the elevation of said sphere is controlled. 12. A spherical rotational device comprising: a. a sphere; b. air bearing means for supporting said sphere comprising:

i. a sphere support housing having an upper concave side to receive said sphere, said upper concave side having cavities in concentric arrangement with said cavities having channels of smaller diameter than said cavities, said channels extending downward within said housing;

ii. balls of larger diameter than said channels received in said cavities;

iii. retaining rings around said cavities to prevent said balls from escaping said cavities; and

iv. means for connecting a pressurized air supply into said cavities through said channels so that pressure exerted on said balls causing them to rise as far as permitted by said retaining rings whereby said sphere is supported by the partial surfaces of said balls that rise above said retaining ring when said air supply is operative;

c. a sleeve rotatable around said circular pedestal;

d. a curved beam of I beam configuration rigidly attached to said sleeve and extending upward from said sleeve over said sphere, said beam comprising:

i. two sets of tracks, one on each side of said beam;

and

ii. two gear racks, one on each side of said beam; e. a freely rotatable vacuum assembly means engageable in one of said sets of tracks for adjustably engaging a portion of the surface of said sphere to establish an axis of rotation for said sphere, said vacuum assembly means having propelling means for moving along said adjacent gear web of said beam; and belt driving means engageable in said set of tracks on the other side of said beam from said vacuum assembly means, said belt driving means engageable on said sphere for revolving said sphere about said spheres axis as established by said vacuum means, said belt driving means having propelling means for moving along said adjacent gear web of said beam.

13. The spherical rotational device described in claim 12 wherein said vacuum assembly means comprises:

a. a vacuum ring engageable on the surface of said sphere;

b. vacuum control means connected to said vacuum ring for selectively engaging and disengaging said vacuum ring from the surface of said sphere, said vacuum control means having a vertical channel extending downward and centrally located to said vacuum ring;

0. a lens positioned at the bottom of said vertical channel; and

d. light means connected to said vacuum control means for sending a beam of light through said vertical channel and through said lens whereby the precise center of rotation axis of said sphere can be determined around which said vacuum ring attaches to said sphere.

k i t 

1. An orbital simulation facility comprising: a. a sphere; b. air bearing means for supporting said sphere; c. independent support means partially surrounding said sphere; d. vacuum means supported by and freely rotatable with respect to said independent support means and adjustably engageable on a portion of the surface of said sphere for establishing an axis of rotation for said sphere; and e. a first driving means engageable on said sphere for revolving said sphere about said sphere''s axis as established by said vacuum means.
 2. The orbital simulation facility described in claim 1 including a vertical drive means to adjust the elevation of said sphere.
 3. The orbital simulation facility described in claim 2 including a remote control means for operating said vacuum means, said first driving means, and said vertical drive means.
 4. The orbital simulation facility described in claim 1 wherein said sphere has a photosensitive surface and the facility includes means for projecting images on said photosensitive surface of said sphere.
 5. The orbital simulator facility described in claim 1 wherein said air bearing means for supporting said sphere comprises: a. A sphere support housing having an upper concave side to receive said sphere, said upper concave side having cavities, with said cavities having channels extending within said housing, said channels being of smaller diameter than said cavities; b. balls of larger diameter than said channels received in said cavities; c. retaining means around said cavities to prevent said balls from escaping said cavities; and d. means for connecting a pressurized air supply to said channels for exerting pressure on said balls causing them to rise as far as permitted by said retaining rings whereby said sphere is supported by the portion of the surface of said balls that rise above said retaining ring when said air supply is turned on.
 6. An orbital simulation facility comprising: a. a sphere; b. air bearing means for supporting said sphere including a circular pedestal extending downward from said air bearing means; c. a sleeve rotatable around said circular pedestal; d. a partial curved beam rigidly attached to said sleeve and extending upward from said sleeve over said sphere; e. vacuum means extending from and freely rotatable with respect to said curved beam and adjustably engageable on a portion of the surface of said sphere for establishing an axis of rotation for said sphere; and f. a driving means extending from said curved beam and engageable on said sphere for revolving said sphere about said sphere''s axis.
 7. The orbital simulator facility described in claim 6 wherein said air bearing means for supporting said sphere comprises: a. a sphere support housing having an upper concave side to receive said sphere, said upper concave side having cavities in concentric arrangement with said cavities having channels of smaller diameter than said cavities extending downward within said housing; b. balls of larger diameter than said channels received in said cavities; c. retaining rings around said cavities to prevent said balls from escaping said cavities; and d. means for connecting a pressurized air supply to said cavities through said channels so that pressure is exerted on said balls causing them to rise as far as permitted by said retaining rings whereby said sphere is supported by the partial surfaces of said balls that rise above said retaining ring when said air supply is operative.
 8. The orbital simulation facility described in claim 6 wherein said vacuum means comprises: a. a vacuum ring engageable on the surface of said sphere; and b. vacuum control means connected to said vacuum ring for seLectively engaging and disengaging said vacuum ring from the surface of said sphere.
 9. The orbital simulation facility described in claim 6 wherein said driving means is belt driven and further comprises: a. a frame slideably attached to said curved beam; b. an arm adjustably connected to said frame so that the distance between said arm and said frame may be adjusted; c. pulleys on both said arm and said frame; d. a belt extending over all of said pulleys; e. a motor to drive said belt; and f. means to engage and disengage said belt from the surface of said sphere.
 10. The orbital simulation facility described in claim 6 wherein said partial curved beam is in a concentric arrangement with said sphere and includes track means in which said vacuum means and said belt driving means are engaged.
 11. The orbital simulation facility described in claim 6 including vertical drive means comprising: a. a horizontal member for supporting said circular pedestal; b. vertical members attached to the extremities of said horizontal member; and c. jacking means connected to said vertical members for raising and lowering said horizontal member whereby the elevation of said sphere is controlled.
 12. A spherical rotational device comprising: a. a sphere; b. air bearing means for supporting said sphere comprising: i. a sphere support housing having an upper concave side to receive said sphere, said upper concave side having cavities in concentric arrangement with said cavities having channels of smaller diameter than said cavities, said channels extending downward within said housing; ii. balls of larger diameter than said channels received in said cavities; iii. retaining rings around said cavities to prevent said balls from escaping said cavities; and iv. means for connecting a pressurized air supply into said cavities through said channels so that pressure exerted on said balls causing them to rise as far as permitted by said retaining rings whereby said sphere is supported by the partial surfaces of said balls that rise above said retaining ring when said air supply is operative; c. a sleeve rotatable around said circular pedestal; d. a curved beam of I beam configuration rigidly attached to said sleeve and extending upward from said sleeve over said sphere, said beam comprising: i. two sets of tracks, one on each side of said beam; and ii. two gear racks, one on each side of said beam; e. a freely rotatable vacuum assembly means engageable in one of said sets of tracks for adjustably engaging a portion of the surface of said sphere to establish an axis of rotation for said sphere, said vacuum assembly means having propelling means for moving along said adjacent gear web of said beam; and f. belt driving means engageable in said set of tracks on the other side of said beam from said vacuum assembly means, said belt driving means engageable on said sphere for revolving said sphere about said sphere''s axis as established by said vacuum means, said belt driving means having propelling means for moving along said adjacent gear web of said beam.
 13. The spherical rotational device described in claim 12 wherein said vacuum assembly means comprises: a. a vacuum ring engageable on the surface of said sphere; b. vacuum control means connected to said vacuum ring for selectively engaging and disengaging said vacuum ring from the surface of said sphere, said vacuum control means having a vertical channel extending downward and centrally located to said vacuum ring; c. a lens positioned at the bottom of said vertical channel; and d. light means connected to said vacuum control means for sending a beam of light through said vertical channel and through said lens whereby the precise center of rotation axis of said sphere can be determined around which said vacuum ring attaches to said sphere. 